My iPhone 4 currently has no battery, I have ordered a new one but there is a time lapse and crucial information on there I need to get off. When I plug my iPhone into a USB wall charger, it will turn on. But it brings up a connect to iTunes screen, but still functions. When I plug it into my computer via USB, the computer does not sustain power to it, and the iPhone apple logo will appear for a few seconds, then the phone shut off. And this process just repeats. How can I make my computer give the iPhone enough power for it to turn on? Thanks.